Pros
High probability of bright colleagues. Interesting 'behind the industry curtains' perspectives. If you can figure it out, it can be very feasible to move around the company and "chart your own path." Many people also do have positive overall experiences, even if working a lot. Most people are like "oooo palantir" when you tell them you work there.
Cons
Working here is a very high variance experience. Palantir confuses "no structure" for "flat structure". It would seem that this attribute that they present as distinguishing feature is actually just a way to elude organizational accountability. There is an appreciable chance that you end up with a bad manager, that doesn't know how to manage or is just checked out, and you'll be super confused all the time. "Mean Girls" type atmosphere, as others have said, meaning people will be saying one thing to your face and another to your manager or they'll say that someone gave such and such feedback even if they didn't. All too easy to get stabbed in the back by dishonest leads/colleagues. You can easily end up stranded with literally no organizational safety net, and it can feel like the Hunger Games. Sudden surprise dismissals on false pretensions, without any explanation. They've been doing quiet firings for months now to try to claw back their stock grants that have appreciated so much, so they can be GAAP profitable for SP500 inclusion, which they ended up not getting. Don't even get me started with the AIP bs.